In conventional wireless communication systems, a network may maintain connections with multiple stations and serve them by scheduling/sending control or data packets in each subframe. A subframe is the basic time unit for the network to schedule data packets to one or more stations. When a data packet is scheduled to a station, the station may receive one or more control channels that include scheduling information. An exemplary control channel is a physical downlink control channel (PDCCH) that includes PDCCH information, each PDCCH information relating to a respective carrier. Accordingly, each of the PDCCH information contains the control information about the corresponding physical downlink shared channel (PDSCH), e.g., Resource Block (RB) allocation, Modulation and Coding Scheme (MCS), HARQ ID, Transport Block Size (TBS), etc.